What would you do if your mother in law forgot your daughter's 3rd birthday?

We all live in the same town. We go to mother in law's for holidays. She remembered my daughter's first 2 birthdays, but so far is 4 days late. My husband and I both have a strained relationship with his mother, but so far she hasn't taken any resentments out on my daughter. There's been no recent drama to explain her behavior. This woman is rude in many other ways, and even her own parents limit their time around her. I'm wondering if I should cut ties completely just to save my daughter's feelings. It makes me sad because family is so important, and my own parents and relatives live several states away. My mother calls nearly every day to talk to her granddaughter, but mother in law calls only if she needs something, and when I call her, she always finds a reason to get off the phone. She never visits us, except on my daughter's previous birthdays. Now that she is 3, she finally understands that her birthday is a special day, so this adds greatly to my disappointment that her other grandma can't show more of an interest. To make matters worse, mother in law has "adopted" another girl, a friend of the family, as her "daughter" and counts this other woman's 4 kids as her grandchildren. She hasn't forgot their birthdays. Should I leave it alone? Or put this selfish woman in her place?